1. Field of the Invention
The present invention relates to a caliper assembly for a disc brake, and more particularly to a caliper assembly for a disc assembly capable of effectively inhibiting eccentric abrasion of pads as well as resultant noise, vibration and so on when a brake is actuated without an increase of additional costs.
2. Description of the Related Art
As well known, a disc brake in the vehicle is provided with a caliper assembly mounted to a disc in a form of straddling a saddle so as to press the disc to generate brake power when being actuated.
Such a caliper assembly is specifically described in U.S. Pat. No. 5,860,496, No. 6,257,378, etc. as example, and includes a carrier fixed to a body, a pair of pads disposed inside the carrier and pressing both surfaces of a disk rotated together with a wheel to generate brake power, and a caliper housing in which a piston is housed.
The pads consist of an inner pad on a piston side and an outer pad on the side opposite to the inner pad. The inner and outer pads are fixedly attached to an inner pad plate and an outer pad plate, respectively.
The caliper housing comprises a bore finished to allow the piston to move forward or backward in the center of a rear part, and a pair of fingers curvedly formed downward on a front part and wrapping the outer pad plate.
The bore has an inner circumferential surface fitted with a seal made of an elastic material so as to restore the piston when a brake fluid pressure is released. The caliper housing is provided about the bore in a surface symmetrical manner.
The disc is disposed so that its outer periphery is partly inserted between the inner pad and the outer pad, and rotates together with the wheel with a predetermined gap maintained from the inner and outer pads when there is no brake action.
In the case where a vehicle having the disc brake constructed as above travels, when its driver steps on a brake pedal, the brake fluid pressure generated from a master cylinder is transmitted inside the bore through a hydraulic line.
Then, the piston goes forward due to transmission of the fluid pressure, and the inner pad plate is pushed toward the disc. Thus, the inner pad is closely pressed on the disc to generate the brake power.
Further, because the fluid pressure is left in the bore, the caliper housing itself moves in the opposite direction. Thereby, the pair of fingers push the outer pad plate toward the disc, and the outer pad is closely pressed and exert on the disc.
When the driver steps off the brake pedal, the piston is restored due to an elastic force of the seal, and the outer pad and the inner pad are spaced apart from the disc again in a predetermined interval.
Meanwhile, for the disc brake as mentioned above, in the case of repeating the brake operation for a long time, eccentric abrasion is generated on a rear side of the inner and outer pads due to momentum caused by a rotational torque. This is responsible for noise and vibration when the brake is actuated.
To prevent this rear-side eccentric abrasion of the pads, U.S. Pat. No. 6,189,659 proposed to eccentrically dispose the piston and the finger pair toward the front side of the disc rotational direction from a center lines of the inner and outer pads, and to balance a force acting on each pad to be uniformly abraded.
However, the conventional caliper assembly structure essentially requires separate finishing processes for varying a shape or a mounting position of each finger so as for each finger to be eccentrically disposed from the centerline of the outer pad. Thus, in terms of the finishing processes, a separate management is needed. This imposes a direct burden on product costs, which is regarded to be unreasonable.